tools/regression/pipe/bigpipetest.c

   1 #include <stdio.h>
   2 #include <fcntl.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <sys/select.h>
   6 #include <string.h>
   7 #include <errno.h>
   8
   9 #define BIG_PIPE_SIZE  64*1024 /* From sys/pipe.h */
  10
  11 /*
  12  * Test for the non-blocking big pipe bug (write(2) returning
  13  * EAGAIN while select(2) returns the descriptor as ready for write).
  14  *
  15  * $FreeBSD$
  16  */
  17
  18 void write_frame(int fd, char *buf, unsigned long buflen)
  19 {
  20     fd_set wfd;
  21     int i;
  22
  23     while (buflen) {
  24         FD_ZERO(&wfd);
  25         FD_SET(fd, &wfd);
  26         i = select(fd+1, NULL, &wfd, NULL, NULL);
  27         if (i < 0) {
  28             perror("select");
  29             exit(1);
  30         }
  31         if (i != 1) {
  32             fprintf(stderr, "select returned unexpected value %d\n", i);
  33             exit(1);
  34         }
  35         i = write(fd, buf, buflen);
  36         if (i < 0) {
  37             if (errno != EAGAIN)
  38                 perror("write");
  39             exit(1);
  40         }
  41         buf += i;
  42         buflen -= i;
  43     }
  44 }
  45
  46 int main()
  47 {
  48     char buf[BIG_PIPE_SIZE];    /* any value over PIPE_SIZE should do */
  49     int i, flags, fd[2];
  50
  51     printf("1..1\n");
  52
  53     if (pipe(fd) < 0) { perror("pipe"); exit(1); }
  54
  55     flags = fcntl(fd[1], F_GETFL);
  56     if (flags == -1 || fcntl(fd[1], F_SETFL, flags|O_NONBLOCK) == -1) {
  57         perror("fcntl");
  58         exit(1);
  59     }
  60
  61     switch (fork()) {
  62         case -1:
  63             perror("fork");
  64             exit(1);
  65         case 0:
  66             close(fd[1]);
  67             for (;;) {
  68                 i = read(fd[0], buf, 256); /* any small size should do */
  69                 if (i == 0) break;
  70                 if (i < 0) { perror("read"); exit(1); }
  71             }
  72             exit(0);
  73         default:
  74             break;
  75     }
  76
  77     close(fd[0]);
  78     memset(buf, 0, sizeof buf);
  79     for (i = 0; i < 1000; i++) write_frame(fd[1], buf, sizeof buf);
  80     printf("ok 1\n");
  81     exit(0);
  82 }